NiMH and my Leaf

[TonyWilliams]

http://en.wikipedia.org/wiki/Alloy_wheel

Magnesium alloy wheels

I had numerous magnesium parts on my two Beech Barons (airplanes). Note, however, that our little LEAFs have a bit of magnesium in them.

Magnesium is a commercially important metal with many uses. It is only two thirds as dense as aluminum. It is easily machined, cast, forged, and welded. It is used extensively in alloys, chiefly with aluminum and zinc, and with manganese. Magnesium alloys were used as early as 1910 in Germany. Early structural uses of magnesium alloys were in aircraft fuselages, engine parts, and wheels. They are now also used in jet-engine parts, rockets and missiles, luggage frames, portable power tools, and cameras and optical instruments. Duralumin and magnalium are alloys of magnesium. The metal is also used in pyrotechnics, especially in incendiary bombs, signals, and flares, and as a fuse for thermite. It is used in photographic flashbulbs and is added to some rocket and missile fuels. It is used in the preparation of malleable cast iron. An important use is in preventing the corrosion of iron and steel, as in pipelines and ship bottoms. For this purpose a magnesium plate is connected electrically to the iron. The rapid oxidation of the magnesium prevents the slower oxidation and corrosion of the iron.

Read more: magnesium: Uses — Infoplease.com http://www.infoplease.com/encyclopedia/science/magnesium-uses.html#ixzz2ATKG21o2" onclick="window.open(this.href);return false;

 

[surfingslovak]

I was not aware the Prius pack was more than 3X the weight of the LEAF pack :lol:

Have you seen that thing? 1.2 kWh? Might as well! :mrgreen:

My NiMH RangerEV has the same Panasonic EV95 batteries, but 25 of them (instead of like 24 in the RAV4EV).

Did the this EV get better range than the RAV4? Was there any change in your vehicle's autonomy based on your experience?

 

[TEG]

My NiMH RangerEV has the same Panasonic EV95 batteries, but 25 of them (instead of like 24 in the RAV4EV).

Did the this EV get better range than the RAV4? Was there any change in your vehicle's autonomy based on your experience

No, the RAV4EV got somewhat better range. Even with a tad less kWh it got more range by being more efficient.
Perhaps better aerodynamics and rolling resistance.
I don't think Ford tried as hard to optimize the various components.

The original NiMH pack is still going 12 years later, but range is maybe 15% less than it was when new.

 

[surfingslovak]

The original NiMH pack is still going 12 years later, but range is maybe 15% less than it was when new.

Very interesting, thank you! How many miles on the truck?

 

[cwerdna]

I was not aware the Prius pack was more than 3X the weight of the LEAF pack :lol:

Have you seen that thing? 1.2 kWh? Might as well! :mrgreen:

Some of the specs are mixed up.

Gen 2 Prius (NHW20) battery specs are mentioned at https://techinfo.toyota.com/techInfoPortal/staticcontent/en/techinfo/html/prelogin/docs/2ndprius.pdf" onclick="window.open(this.href);return false;.

Gen 1 Prius (first gen to be sold outside Japan aka NHW11) battery specs at https://techinfo.toyota.com/techInfoPortal/staticcontent/en/techinfo/html/prelogin/docs/1stprius.pdf" onclick="window.open(this.href);return false;.

There's a table at http://www.myprius.co.za/models.htm" onclick="window.open(this.href);return false;. There is a bit of weight discrepancy, between sources.

One should be able to get to other Toyota ERGs at by clicking on Emergency Response & Hybrid Information at the bottom of https://techinfo.toyota.com/public/main/erg.html" onclick="window.open(this.href);return false;.

 

[TEG]

The original NiMH pack is still going 12 years later, but range is maybe 15% less than it was when new.

Very interesting, thank you! How many miles on the truck?

Only 20K! I had a much shorter commute before, and previously it sat nearly unused at an Air Force base for the first 5 years of its' life.

I already have almost as many miles on the LEAF now after having it for only 18 months.

 

[cwerdna]

As a side note, at http://avt.inl.gov/hev.shtml" onclick="window.open(this.href);return false;, if you search for battery, you can find some of their test results on hybrid car batteries at the end of their test/160K miles.

There might be a few others that aren't on this page (e.g. I think http://avt.inl.gov/pdf/hev/end_of_life_test_1.pdf" onclick="window.open(this.href);return false; isn't on the above page).

But yes, the capacity and energy density of NiMH batteries used in Priuses is quite low.

 

[DaveinOlyWA]

The battery pack in the Prius is quite large, and it weighs a ton.

I was not aware the Prius pack was more than 3X the weight of the LEAF pack :lol:

you are missing a character there... that should be like "1/3" the weight. i think you are referring to the RAV 4 EV pack of 2000's. now that pack was HEAVY but still not 3 times heavier. maybe 2 times?

 

[Ingineer]

Over 2 years ago, I converted my 2008 Prius to a Plug-in using A123 Lithium cells. The original pack with all it's hardware (housing, cooling system, etc) weighed in at ~90lbs according to my scale, which was all removed. I then installed ~140lbs of hardware consisting of the ~6.5kWh pack (usable), charger, wiring, mounting hardware, etc. So my net gain was 50lbs, which was so little that I didn't need any suspension changes.

The Prius then gained an all EV range of about 40 miles city or 20 miles highway, versus about ~1 mile from the original (heavily coddled) Ni-Mh setup. Even when not plugged in, this Prius went from ~45mpg to 51mpg. When plugged in regularly, it was "off the scale" (over 99mpg which is the highest it would record), even with my lead-foot!

The A123 cells are amazing performers, though not as energy dense as some of the various chemistry variants we have available now. They trade some density for ruggedness as a worthwhile (IMHO) compromise. These are now over 3 years old, and have been in use in my Prius for over 2 with zero loss of capacity. (In fact, they are still performing at over their factory spec)

They had been QC'd at high temperatures (130+ degrees) at least a dozen times prior to installation in my Prius while in use in a high-performance race car.

I can't say that any Nickel-based chemistry I am aware of is anywhere nearly this good all-around. I had a 2100lb ~40kWh pack of flooded Saft Ni-Cads in my 1989 G-van. They still have over 80% of their usable capacity after over 25 years and severe mistreatment, including sitting in the California desert for almost 8 years. They are good for certain uses, but for an EV they are a really poor choice due to the maintenance requirements.

Also, we ain't seen nothin' yet! Wait until we can get our hands on Lithium-Air!

-Phil

 

[surfingslovak]

Also, we ain't seen nothin' yet!

Great post, Phil. This is painful to watch, but in the name of science:

[youtube]http://www.youtube.com/watch?v=WkKRqaNPIBE[/youtube]

 

[DaveinOlyWA]

Also, we ain't seen nothin' yet!

Great post, Phil. This is painful to watch, but in the name of science:

[youtube]http://www.youtube.com/watch?v=WkKRqaNPIBE[/youtube]

looks like they'll burn up the starter before the battery dies

 

[adric22]

I've removed a Prius battery before on a 1st gen. I can assure anyone here that it is a two person job. THey are quite heavy.
I've always wondered why Toyota picked the style of battery they did. I am sure their engineers had good reasons. But being that they want a voltage at the motor of nearly twice the battery pack's voltage it seems like a smaller cell setup with higher total pack voltage would have made more sense. Does the Leaf do any conversion to a higher voltage for the motor?

 

[DaveinOlyWA]

I've removed a Prius battery before on a 1st gen. I can assure anyone here that it is a two person job. THey are quite heavy.
I've always wondered why Toyota picked the style of battery they did. I am sure their engineers had good reasons. But being that they want a voltage at the motor of nearly twice the battery pack's voltage it seems like a smaller cell setup with higher total pack voltage would have made more sense. Does the Leaf do any conversion to a higher voltage for the motor?

i picked one up with a partner and it was very manageable. i would guess around 100-120 lbs. there were "some" things on it but nothing like a LEAF pack which has 3 pieces each weighing near 200 lbs are they not??

seems to me i read the LEAF pack weight with accessories is over 600 lbs?

 

[Ingineer]

I've removed a Prius battery before on a 1st gen. I can assure anyone here that it is a two person job. THey are quite heavy.
I've always wondered why Toyota picked the style of battery they did. I am sure their engineers had good reasons. But being that they want a voltage at the motor of nearly twice the battery pack's voltage it seems like a smaller cell setup with higher total pack voltage would have made more sense. Does the Leaf do any conversion to a higher voltage for the motor?

On the 1st gen, they did just that; more cells. On Gen 2 and up, they now use the boost converter. The problem is that this adds conversion loss, and it's limited in power. (about 21kW in a Gen 2)

When Toyota was designing the Prius, decent Lithium-Ion was only a pipe dream. Within a few years, I predict you will no longer see Ni-Mh used in Hybrids, despite the now wide-open patent status. Lithium is now better, and most importantly, the automakers are learning (mostly) how to make it and how to use it.

-Phil

 

[sub3marathonman]

I can't say that any Nickel-based chemistry I am aware of is anywhere nearly this good all-around. I had a 2100lb ~40kWh pack of flooded Saft Ni-Cads in my 1989 G-van. They still have over 80% of their usable capacity after over 25 years and severe mistreatment, including sitting in the California desert for almost 8 years. They are good for certain uses, but for an EV they are a really poor choice due to the maintenance requirements.

-Phil

WOW, he had a G-Van!!!

I remember a G-Van being for sale out in Arizona at some point long ago. I remember corresponding with the guy, who seemed like a good guy.

I heard you had to be an electronics wizard to keep them running. Oh, of course, that explains why Phil was able to drive it.

That got me thinking about the TEVan, another interesting early EV. A guy in Colorado had one for sale, I wished I could have checked it out. A website is: http://tzev.com/1993_tevan_.html" onclick="window.open(this.href);return false; , and an interesting point is that he actually made a range extending trailer for it: http://tzev.com/1993_tevan_RXT-B.html" onclick="window.open(this.href);return false;

I had a 1997 S10-EV, but never could get worthwhile PbA batteries for it. The Panasonic EV-1260 was a spectacular battery, but uniquely shaped, so there was no easy replacement. There was discussion that they were removed from the U.S. market, http://www.evdl.org/archive/index.html#nabble-td421765" onclick="window.open(this.href);return false; , and I actually did try to get some from Japan but it proved impossible.

 

[Ingineer]

I heard you had to be an electronics wizard to keep them running. Oh, of course, that explains why Phil was able to drive it.

Yes, the controllers (Chloride) were definitely somewhat fragile. Keeping the brushgear in good shape and insuring you had a stiff pack were several ways to insure you didn't have problems.

Mine was (and still is for the new owner) quite reliable, but then again, I did a bunch of tweaking.

-Phil

 

[Nubo]

http://en.wikipedia.org/wiki/Alloy_wheel

Magnesium alloy wheels

I had numerous magnesium parts on my two Beech Barons (airplanes). Note, however, that our little LEAFs have a bit of magnesium in them.

Magnesium is a commercially important metal with many uses. It is only two thirds as dense as aluminum. It is easily machined, cast, forged, and welded. It is used extensively in alloys, chiefly with aluminum and zinc, and with manganese. Magnesium alloys were used as early as 1910 in Germany. Early structural uses of magnesium alloys were in aircraft fuselages, engine parts, and wheels. They are now also used in jet-engine parts, rockets and missiles, luggage frames, portable power tools, and cameras and optical instruments. Duralumin and magnalium are alloys of magnesium. The metal is also used in pyrotechnics, especially in incendiary bombs, signals, and flares, and as a fuse for thermite. It is used in photographic flashbulbs and is added to some rocket and missile fuels. It is used in the preparation of malleable cast iron. An important use is in preventing the corrosion of iron and steel, as in pipelines and ship bottoms. For this purpose a magnesium plate is connected electrically to the iron. The rapid oxidation of the magnesium prevents the slower oxidation and corrosion of the iron.

Read more: magnesium: Uses — Infoplease.com http://www.infoplease.com/encyclopedia/science/magnesium-uses.html#ixzz2ATKG21o2" onclick="window.open(this.href);return false;

I seem to recall that, at one point, over HALF of the world's Magnesium production was being used to produce engine blocks for the Volkswagen Beetle.

 

[TonyWilliams]

I seem to recall that, at one point, over HALF of the world's Magnesium production was being used to produce engine blocks for the Volkswagen Beetle.

It wouldn't surprise me. They burn those engine blocks in the desert for camp fires. Spectacular fires.

 

[surfingslovak]

My NiMH RangerEV has the same Panasonic EV95 batteries, but 25 of them (instead of like 24 in the RAV4EV).

You might like this YouTube video, if you haven't seen it already. It ties nicely into the topic of this thread as well.

[youtube]http://www.youtube.com/watch?v=OxEHZCBza6w[/youtube]

 

[jlsoaz]

My NiMH RangerEV has the same Panasonic EV95 batteries, but 25 of them (instead of like 24 in the RAV4EV).

You might like this YouTube video, if you haven't seen it already. It ties nicely into the topic of this thread as well.

[youtube]http://www.youtube.com/watch?v=OxEHZCBza6w[/youtube]

Very cool.